In an effort to both control and monitor access, state-of-the-art contemporary access security systems have begun to electrically couple the hardware of individual locks to a central, or host, computer. This enables the systems at a minimum, to monitor the operation of each lock and more commonly, to additionally control access to the space guarded by each lock by the expedient of controlling, or at least regulating operation of individual locks. Although some systems rely simply either wholly, or partially, upon recognition of a code borne by a pass, or credential, that contains a memory (e.g., a magnetic strip or embedded memory chip) bearing a code unique to the pass, more elaborate systems such as the ELECTRONIC SECURITY SYSTEM of R. G. Hyatt, Jr., et al. disclosed in U.S. Pat. No. 5,140,317 issued on 18 Aug. 1992, use both an electronic lock mechanism and an electronic key, both of which are provided with a microprocessor and a memory storing an identification code. More recent efforts such as the DUAL CONTROL MODE LOCK of T. J. DiVito, et al., U.S. Pat. No. 5,423,198 issued on 13 Jun. 1995, endeavors to further enhance access security by first having the blade of a key bearing the correct profile and bitting transmit an enable signal upon insertion into the keyway of a particular rekeyable locking mechanism, and then having a second coded signal electromagnetically displace one or more pin tumbler stacks to enable rotation of the plug relative to the cylinder.
It has been my observation that these access security systems tend to require complete replacement of each previously installed locking mechanism. I have found that this is not always feasible because some locks have a cylinder formed as an integral part of the secured item (e.g. a hospital drug cart), while other items and areas lack sufficient space to accommodate replacement of an existing mechanical lock with the larger volume of a contemporary electromechanical lock. Moreover, contemporary electromechanical lock systems typically require that each lock be electrically wired into a network with either a source of power or a data or control bus. While this is possible with many architectural applications and with secured items such as a coin box of a pay telephone, in other situations I have found that either the remote location of the lock, the difficulty in stringing the necessary wiring, or customs in the particular industry concerning placement of a lock on the secured item, or area, make the installation of an electromechanical lock that is wired into a network impractical.
I have also noticed that both the expense of the complete replacement of each locking mechanism and the expense of the replacement electromechanical locking system have limited the market for such systems to users where either enhanced security is paramount (e.g., hospital drug cabinets) or excess system costs are not a disadvantage because the user (e.g., a regulated utility such as a telephone company that installs electromechanical locks on the coin boxes of its pay telephones) is able to claim an annual return based upon the cost of savings generated by the system. I have discovered that although both classes of users would be able to attain the same level of security from less elaborate systems, the willingness of such users to readily bear these costs as well as the ages old illusion of security concomitant with expense, has hidden the possibility of improving upon current access security systems.
Moreover, I have found that despite their innate complexity, many contemporary electromechanical lock systems are able to provide only a single level of access security; thus the cost of equipping each user to use a particular lock remains the same—each user must have the same expensive battery powered microprocessor controlled key, despite the fact that different users of that lock may have different levels of access via that lock. Loss or damage of the microprocessor controlled key can not, in my observation, be minimized by the owner of the lock. Furthermore, electromechanical locking systems tend, because of their excessively elaborate designs, to be unique to their manufacturers. Accordingly, users become captive to their initially selected manufacturer. Consequently, other potential classes of users subject to considerations of costs for replacement of existing locks, costs of the replacement systems as well as costs of operation of the replacement and costs of periodic repair and maintenance, have been denied the benefits of less expensive electromechanical locking systems able to provide the same level of access security, despite the fact that security is also a paramount concern of such users (e.g. a prison or other governmentally funded institution).